"Has been waiting" should be your answer. a simple predicate is the verb or verb phrase in the sentence and it usually tells what the subject does.
Answer:
C
Explanation:
The commas in this sentence r used for 2 reasons.
1. "Unless I'm mistaken" is a clause, so u "pause" after it with a comma
2. Always put commas in between descriptive words.. of the same subject
;)
